Neurostimulation systems are devices that generate electrical pulses and deliver the pulses to nerve tissue to treat a variety of disorders. Spinal cord stimulation (SCS) is an example of neurostimulation in which electrical pulses are delivered to nerve tissue in the spine for the purpose of chronic pain control. While a precise understanding of the interaction between the applied electrical energy and the nervous tissue is not fully appreciated, it is known that application of an electrical field to spinal nervous tissue (i.e., spinal nerve roots and spinal cord bundles) can effectively mask certain types of pain transmitted from regions of the body associated with the stimulated nerve tissue. Specifically, applying electrical energy to the spinal cord associated with regions of the body afflicted with chronic pain can induce “paresthesia” (a subjective sensation of numbness or tingling) in the afflicted bodily regions. Thereby, paresthesia can effectively mask the transmission of non-acute pain sensations to the brain.
Neurostimulation systems typically include a pulse generator and one or several leads. The pulse generator is the device that generates the electrical pulses. The pulse generator is typically implanted within a subcutaneous pocket created under the skin by a physician. The leads are used to conduct the electrical pulses from the implant site of the pulse generator to the targeted nerve tissue. The leads typically include a lead body of an insulative polymer material with embedded wire conductors extending through the lead body. Electrodes on a distal end of the lead body are coupled to the conductors to deliver the electrical pulses to the appropriate nerve tissue.
Stimulation paddle leads dispose a plurality of electrodes (for example, two, four, eight, or sixteen) arranged in one or more columns on a paddle structure. It is typical that implanted SCS paddles are transversely centered over the physiological midline of a patient. In such position, multiple columns of electrodes are well suited to address both unilateral and bilateral pain. A multi-column SCS paddle also enables reliable positioning of a plurality of electrodes that does not deviate over time. In particular, the probability of migration of an SCS paddle after implantation is significantly lower than the probability of migration of percutaneous leads. Additionally, SCS paddles are capable of being sutured in place.
However, given the dimensions of conventional SCS paddles, a surgical procedure is necessary for implantation. The surgical procedure (a “partial laminectomy”) requires the resection and removal of certain vertebral structures to allow both access to the dura and proper positioning of the SCS paddle. The invasive nature of the surgical procedure requires some amount of time for patient recovery and, in some cases, could cause long-term complications for the patient. Additionally, due to the relatively complicated nature of the surgical procedure, the procedure is typically performed by a neurosurgeon.
Additionally, it is noted that typical assembly procedures for electrically coupling a lead body to a paddle structure are not only cumbersome and expensive, but also create a number of natural, easy breakage points. Specifically, conventional couplings between lead bodies and paddle structures involve welding a jumper wire between contacts and conductive wires of the lead body. Accordingly, conventional paddle lead fabrication methods may involve undue expense and lower than desired manufacturing yields.